Portable air compressor



FIG. 1 is a perspective view on an enlarged scale of a portable air compressor showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right end elevational view thereof;

FIG. 5 is a left end elevational view thereof;

FIG. 6 is a top plan view thereof; and

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a portable air compressor, substantially as shown and described. 